Note 15 - Stock-based Compensation Plan - Stock Option Activity (Details) - $ / shares	12 Months Ended
	Dec. 31, 2021	Dec. 31, 2020
Options outstanding, number of shares (in shares)	438,200	506,810
Options outstanding, weighted average exercise price (in dollars per share)	$ 6.25	$ 6.89
Granted, number of shares (in shares)	282,404	113,980
Granted, weighted average exercise price (in dollars per share)	$ 11.77	$ 3.49
Exercised, number of shares (in shares)	231,185	(0)
Canceled, number of shares (in shares)	80,550	182,590
Canceled, weighted average exercise price (in dollars per share)	$ 9.55	$ 6.31
Exercised, weighted average exercise price (in dollars per share)	$ 6.85
Options outstanding, number of shares (in shares)	408,869	438,200
Options outstanding, weighted average exercise price (in dollars per share)	$ 9.07	$ 6.25